From 10ee2acdd26a7f1298c6f6d6b7af9b469fe29b87 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sat, 4 May 2024 14:41:41 +0200
Subject: Merging upstream version 1.70.0+dfsg2.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 vendor/gix-chunk/src/file/write.rs | 136 +++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 vendor/gix-chunk/src/file/write.rs

(limited to 'vendor/gix-chunk/src/file/write.rs')

diff --git a/vendor/gix-chunk/src/file/write.rs b/vendor/gix-chunk/src/file/write.rs
new file mode 100644
index 000000000..8189140fe
--- /dev/null
+++ b/vendor/gix-chunk/src/file/write.rs
@@ -0,0 +1,136 @@
+use crate::file::{index::Entry, Index};
+
+mod write_chunk {
+    use std::collections::VecDeque;
+
+    use crate::file::index;
+
+    /// A [`Write`][std::io::Write] implementation that validates chunk sizes while allowing the user to know
+    /// which chunk is to be written next.
+    pub struct Chunk<W> {
+        chunks_to_write: VecDeque<index::Entry>,
+        inner: W,
+        next_chunk: Option<index::Entry>,
+        written_bytes: usize,
+    }
+
+    impl<W> Chunk<W>
+    where
+        W: std::io::Write,
+    {
+        pub(crate) fn new(out: W, chunks: VecDeque<index::Entry>) -> Chunk<W>
+        where
+            W: std::io::Write,
+        {
+            Chunk {
+                chunks_to_write: chunks,
+                inner: out,
+                next_chunk: None,
+                written_bytes: 0,
+            }
+        }
+    }
+
+    impl<W> std::io::Write for Chunk<W>
+    where
+        W: std::io::Write,
+    {
+        fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+            let written = self.inner.write(buf)?;
+            self.written_bytes += written;
+            Ok(written)
+        }
+
+        fn flush(&mut self) -> std::io::Result<()> {
+            self.inner.flush()
+        }
+    }
+
+    impl<W> Chunk<W> {
+        /// Return the inner writer - should only be called once there is no more chunk to write.
+        pub fn into_inner(self) -> W {
+            self.inner
+        }
+        /// Return the next chunk-id to write, if there is one.
+        pub fn next_chunk(&mut self) -> Option<crate::Id> {
+            if let Some(entry) = self.next_chunk.take() {
+                assert_eq!(
+                    entry.offset.end,
+                    self.written_bytes as u64,
+                    "BUG: expected to write {} bytes, but only wrote {} for chunk {:?}",
+                    entry.offset.end,
+                    self.written_bytes,
+                    std::str::from_utf8(&entry.kind)
+                )
+            }
+            self.written_bytes = 0;
+            self.next_chunk = self.chunks_to_write.pop_front();
+            self.next_chunk.as_ref().map(|e| e.kind)
+        }
+    }
+}
+pub use write_chunk::Chunk;
+
+/// Writing
+impl Index {
+    /// Create a new index whose sole purpose is to be receiving chunks using [`plan_chunk()`][Index::plan_chunk()] and to be written to
+    /// an output using [`into_write()`][Index::into_write()]
+    pub fn for_writing() -> Self {
+        Index {
+            will_write: true,
+            chunks: Vec::new(),
+        }
+    }
+    /// Plan to write a new chunk as part of the index when [`into_write()`][Index::into_write()] is called.
+    pub fn plan_chunk(&mut self, chunk: crate::Id, exact_size_on_disk: u64) {
+        assert!(self.will_write, "BUG: create the index with `for_writing()`");
+        assert!(
+            !self.chunks.iter().any(|e| e.kind == chunk),
+            "BUG: must not add chunk of same kind twice: {:?}",
+            std::str::from_utf8(&chunk)
+        );
+        self.chunks.push(Entry {
+            kind: chunk,
+            offset: 0..exact_size_on_disk,
+        })
+    }
+
+    /// Return the total size of all planned chunks thus far.
+    pub fn planned_storage_size(&self) -> u64 {
+        assert!(self.will_write, "BUG: create the index with `for_writing()`");
+        self.chunks.iter().map(|e| e.offset.end).sum()
+    }
+
+    /// Return the amount of chunks we currently know.
+    pub fn num_chunks(&self) -> usize {
+        self.chunks.len()
+    }
+
+    /// After [planning all chunks][Index::plan_chunk()] call this method with the destination to write the chunks to.
+    /// Use the [Chunk] writer to write each chunk in order.
+    /// `current_offset` is the byte position at which `out` will continue writing.
+    pub fn into_write<W>(self, mut out: W, current_offset: usize) -> std::io::Result<Chunk<W>>
+    where
+        W: std::io::Write,
+    {
+        assert!(
+            self.will_write,
+            "BUG: create the index with `for_writing()`, cannot write decoded indices"
+        );
+        // First chunk starts past the table of contents
+        let mut current_offset = (current_offset + Self::size_for_entries(self.num_chunks())) as u64;
+
+        for entry in &self.chunks {
+            out.write_all(&entry.kind)?;
+            out.write_all(&current_offset.to_be_bytes())?;
+
+            current_offset += entry.offset.end;
+        }
+
+        // sentinel to mark end of chunks
+        out.write_all(&0u32.to_be_bytes())?;
+        out.write_all(&current_offset.to_be_bytes())?;
+
+        Ok(Chunk::new(out, self.chunks.into()))
+    }
+}
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